Platelet protein disulfide isomerase promotes glycoprotein ib&-mediated platelet-neutrophil interactions under thromboinflammatory conditions

Jing Li, Kyungho Kim, Si Yeon Jeong, Joyce Chiu, Bei Xiong, Pavel A. Petukhov, Xiangrong Dai, Xiaoyi Li, Robert K. Andrews, Xiaoping Du, Philip J. Hogg, Jaehyung Cho

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Background: Platelet-neutrophil interactions contribute to vascular occlusion and tissue damage in thromboinflammatory disease. Platelet glycoprotein Ib& (GPIb&), a key receptor for the cell-cell interaction, is believed to be constitutively active for ligand binding. Here, we established the role of platelet-derived protein disulfide isomerase (PDI) in reducing the allosteric disulfide bonds in GPIb& and enhancing the ligand-binding activity under thromboinflammatory conditions. Methods: Bioinformatic analysis identified 2 potential allosteric disulfide bonds in GPIb&. Agglutination assays, flow cytometry, surface plasmon resonance analysis, a protein-protein docking model, proximity ligation assays, and mass spectrometry were used to demonstrate a direct interaction between PDI and GPIb& and to determine a role for PDI in regulating GPIb& function and platelet-neutrophil interactions. Also, real-Time microscopy and animal disease models were used to study the pathophysiological role of PDI-GPIb& signaling under thromboinflammatory conditions. Results: Deletion or inhibition of platelet PDI significantly reduced GPIb&-mediated platelet agglutination. Studies using PDI-null platelets and recombinant PDI or Anfibatide, a clinical-stage GPIb& inhibitor, revealed that the oxidoreductase activity of platelet surface-bound PDI was required for the ligand-binding function of GPIb&. PDI directly bound to the extracellular domain of GPIb& on the platelet surface and reduced the Cys4-Cys17 and Cys209-Cys248 disulfide bonds. Real-Time microscopy with platelet-specific PDI conditional knockout and sickle cell disease mice demonstrated that PDI-regulated GPIb& function was essential for platelet-neutrophil interactions and vascular occlusion under thromboinflammatory conditions. Studies using a mouse model of ischemia/reperfusion-induced stroke indicated that PDI-GPIb& signaling played a crucial role in tissue damage. Conclusions: Our results demonstrate that PDI-facilitated cleavage of the allosteric disulfide bonds tightly regulates GPIb& function, promoting platelet-neutrophil interactions, vascular occlusion, and tissue damage under thromboinflammatory conditions.

Original languageEnglish
Pages (from-to)1300-1319
Number of pages20
Issue number10
StatePublished - Mar 5 2019


  • blood platelets
  • glycoprotein Ibalpha
  • inflammation
  • neutrophils
  • protein disulfide isomerase


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